Clinton says she’s the toughest

Pushing for a strong win to keep her White House hopes alive, Democrat Hillary Clinton touted her toughness on Monday ahead of a showdown with presidential rival Barack Obama in Pennsylvania.

Clinton, favored to win Tuesday’s contest, needs a big margin of victory to boost her chances of catching Obama in the Democratic race and to head off renewed calls to end her candidacy.

"We need to really bear down. The last day is here, and the entire world is watching," Clinton told a rally in the blue-collar city of Scranton, where her father grew up. "What’s important today and tomorrow is that we turn out the vote."

Clinton and Obama are dueling for the Democratic nomination to face Republican John McCain in November’s presidential election. Both candidates spent the day scouring Pennsylvania in a late hunt for support.

Voting in the state ends at 8 p.m. EDT (midnight GMT) with first results available soon afterward.

Clinton, a New York senator and former first lady, launched a television ad stressing her ability to handle "the toughest job in the world" and featuring images of al Qaeda leader Osama bin Laden and damage from Hurricane Katrina.

"You need to be ready for anything — especially now, with two wars, oil prices skyrocketing and an economy in crisis," the ad’s narrator says, throwing in a reference to a famous saying by former Democratic President Harry Truman.

"If you can’t stand the heat, get out of the kitchen," the narrator says. "Who do you think has what it takes?"

Clinton has questioned whether Obama, a first-term Illinois senator, has the experience to be commander in chief. Obama campaign spokesman Bill Burton noted the bin Laden imagery in the ad.

"It’s ironic that she would borrow the president’s tactics in her own campaign and invoke bin Laden to score political points," he said. "We already have a president who plays the politics of fear, and we don’t need another."

After several days of sharp attacks on Clinton, Obama began the final day focused on pocketbook issues such as the cost of gasoline, taxes and jobs.

"We’ve had a terrific contest between myself and Senator Clinton and the other candidates who were originally involved," Obama told a forum with middle-class voters in the town of Blue Bell outside of Philadelphia.

Obama leads Clinton in delegates to the August convention in Denver, but neither can clinch the nomination without the help of superdelegates — nearly 800 party insiders who are free to support either candidate.

Clinton hopes a big win in Pennsylvania and a strong run through the nine remaining Democratic contests will convince superdelegates she is the candidate who can capture the big states crucial to a November election victory.

Her financial statement filed with the Federal Election Commission late on Sunday showed she raised less than half of what Obama did in March — $20.9 million to $42.8 million — and had more debt than cash at the end of the month.

Clinton has resisted calls from Obama supporters to pull out of the race and let him focus on the election battle against McCain.

McCain launched a five-day tour on Monday of economically struggling areas rarely visited by Republicans. He opened in Selma, Alabama, at a landmark of the U.S. civil rights movement — the bridge where state police attacked more than 500 civil rights demonstrators in 1965 on a day known as "Bloody Sunday."

McCain spoke highly of Democratic Rep. John Lewis of Georgia — an Obama supporter — who took part in the Selma march and was beaten by police.

McCain’s trip also will take him to the hard-hit steel town of Youngstown, Ohio, the Appalachia region of Kentucky and hurricane-stricken New Orleans.

(Additional reporting by Steve Holland and Caren Bohan; writing by John Whitesides, editing by David Wiessler)